Tray crawler



United States Patent Inventor Donald F. Drennan Rte. 7, Laurel, Mississippi 39440 App]. No. 773,236 Filed Nov. 4, 1968 Patented Nov. 24, 1970 TRAY CRAWLER 4 Claims, 8 Drawing Figs.

Int. Cl. B611) 3/02 Field of Search 105/150,

[56] References Cited UNITED STATES PATENTS 1,816,031 7/1931 Willis 105/150 3,168,874 2/1965 Atanas0ff.... 105/150- 3,446,158 5/1969 Pettit 105/153 Primary Examiner-Arthur L. LaPoint ABSTRACT: A crawling device for moving around to the lip of a tray, the device comprising a unit including a drive wheel which rides along the upper surface of the tray lip and a pair of binding wheels which bear against the underside of the tray lip, the drive wheel being powered by an electric motor operated by a dry cell battery that is carried by the unit and a unit carrying a rope clamp arm.

Patented Nov. 24, 1970 3,541,971

Sheet '1 of 2 4: 1' l I v I li //V r//vr'oz 1;; 4! ,3- DOA/4L0 F pea MW Patented Nov. 24, 1970 3,541,971

Sheet 2 of2 TRAY CRAWLER SPECIFICATION This invention relates generally to tray crawlers.

A principal object of the present invention to provide a tray crawler which will be used to pull rope along a cable tray.

Another object of the present invention is to provide a tray crawler which applies the rope to the tray more conveniently and much more rapidly than would be possible by a workman crawling in the tray. 1

Other objects of the present invention are to provide a tray crawler which issimple in design, inexpensive to manufacture, rugged in construction, easy to use and efficient in operation.

These and other objects will become readily evident upon a study of the following specification and the accompanying drawings wherein:

FIG. 1 is an end elevation view of the present invention shown partly in cross section;

FIG. 2 is a side elevation view'thereof shown partly in cross section;

FIG. 3 is an inside elevation view thereof;

FIG. 4 is an elevation view of a contact wheel upon the tray p;

FIG. 5 is an end elevation view ofa modified form oftray lip including an insulated strip;

FIG. 6 is an end elevation view of a modified version of the tray crawler; v

FIG. 7 is a front elevation view thereof shown partly in cross section illustrating the electrical circuit thereof; and

FIG. 8 is a front view thereof.

Referring now to the drawings in detail, and more particularly to FIGS. 1 through 5, the reference numeral 10 represents a tray crawler according to the present invention wherein there is a moveable unit 11 which can travel along a lip 12, which forms a flange'extending horizontally around the upper edge ofa tray 13. i The unit 11 includes a housing 14 which encloses 6 to 12 volt dry cell batteries 15, which are connected by conductor wires 16 to an electric switch 17 and to an electric motor 18. v

The switch 17 includes a manually operated control knob 19 for selectively positioning the switch to either drive the motor forward, reverse or to shut it off.

The motor has an output shaft 20, having a bevel gear 21 mounted thereupon, the bevel gear 21 engaging a bevel gear 22 upon a horizontal shaft 23, upon which there is mounted a drive wheel 24. The drive wheel is provided with a rubber face so as to form a strong frictional grasp of the upper surface of the tray lip 12. The shaft 23 is supported within bearings 25 of legs 26 integral with housing 14. I

An arm 27 is secured at its upper end to one side of the housing 14, the lower end ofthe arm 27 having a horizontal bar 28 integrally formed therewith, the bar 28 having a pair of spaced apart, vertically upstanding guide posts 29 which serve as tracks along which a frame 30 is vertically moveable.

The frame 30 comprises a horizontal bar 31 having integral upstanding pairs of brackets 32, each bracket being of U- shaped configuration between which a shaft 33 is supported, each shaft 33 carrying a pivotally free binding wheel 34 which bears against the underside 35 of the tray lip 12. In order to insure that a proper frictional grasp of the drive wheel is attained against the upper side 36 of the lip 12, the frame 30 is vertically moveableso that the binding wheels 34 can bear with greater or less friction against the underside ofthe lip.

The vertical movement of the frame 30 is accomplished by means of a binding screw 37 attached at its upper end rotatably free within the frame 31, the screw 37 having a thread which is threadingly engaged within a threaded opening 38 in the bar 28, as shown in FIG. 2. The lower end of the binding screw is provided with a manually operative head 39, and a lock nut 40 is threadingly mounted upon the binding screw so as to secure the same in a fixed position respective to the bar 28, thereby locking the frame 30 at a selected elevation upon the guide posts 19.

, The unit 11 further includes a rope clamp arm 41 depending from the housing 14, the arm 41 having an opening 42 at the lower end thereof for receiving a rope. The rope clamp arm may be 'spring-tensioned so to open an electrical circuit when the crawler reaches a maximum pull. As shown in FIG. 3 of the drawing, wires from the switch 17 is hooked in series to a pair of contact wheels 43 and 44 which are made to ride in front and back of the drive wheel 24. A pair of support wheels 45 which are located upon arm 41 serve to prevent strain of the rope to pull the crawler in a sideward direction. The rope clamp arm 41 may be selectively moved between the vertical direction, as is illustrated in solid lines of FIG. [to a horizontal position as is indicated by phantom lines in FIG. I.

.It is to be noted that each binding wheel 34 is rubber surfaced in a like manner as the drive wheel 24.

A swivel and lock enables the crawler to be attached in a selected position on the tray.

It is to be noted that as shown in FIG. 5, the lip 12 of the tray is covered with an insulated strip 47 in certainareas so as to open an electric circuit to the motor of the unit 11 and thus stop the crawler unit. 1

In operative use, the unit 11 may be made to move either forwardly or in a reverse'direction around the lip ofa tray by means of controlling the switch knob 19, thus allowing the unit-11 to travel. The frictional tension of the unit respective to the tray lip may be controlled by the screw 37, and the device may be selectively stopped by means of the switch control knob 19 or by means of the positioned insulated strips 47 in particular locations.

In the modified version of the present invention, as is illustrated in FIGS. 6 through 8, the unit 60 includes housing 61 for motor 62 operated by dry cell batteries 63. A switch 64 controlled knob 65, serves to activate the motor which drives through a gear box 66 and an output motor shaft 67 which car- .ries the drive wheel 68.

tion includes arm 71 secured to housing 61, the arm having a bar 72 at its lower end which supports the spaced apart posts 73 that serve as guides for the frame 74 which includes the U- shaped brackets 75 supporting shaft 76 upon which the binding wheels 70 are carried. Binding the frame 74 to a selected elevation.

Contact wheels 78 are carried in a like manner as the contact wheels above described, the contact wheels being in cir cuit with the switch 64. As shown in FIG. 6, it is to be noted that in the present version ofthe invention, a lock and pivot 79 is provided for the arm 80 swingback.

Various other features may be incorporated into the present invention such as tapping a thread into a splice plate for using a screw which will make it easier and faster than using a hard head'screw and nut, and which will allow the tray crawler to move past a splice without catchingon the protruding screws that would block the passage through of the channel. The expansion joint plate may fit the contour ofthe inside channel on the outside of the tray and be attached only to one section of the tray. The other end of the plate may be free to slide back and forth in the channel of the other section of the tray when it expands. This expansion joint plate may also act as a bridge for the tray crawler and will help support the tray. The expansion joint now comprises a four inch gap between the two sections of the tray. The expansion plate will have to fit where the crawler would not lose traction when crossing the expansion joint.

Likewise, the present invention may include an overload switch on the tray crawler. The switch can be installed by providing a spring tensioned means to open the circuit when the pull becomes excessively great by the rope. The spring can be attached to the arm of the rope clamp.

While various changes may be made in the detailed construction it is understood that such changes will be within the spirit and scope of the present invention as is defined by the appended claims.

I claim:

1. In a tray crawler assembly, the combination of a tray crawler unit and a tray, said tray including an upstanding side wall having at its upper edge a horizontally and outwardly extending flange forming a lip, said lip providing a track upon which said tray crawler unit may travel, said tray crawler unit including a housing incorporating wheel means engaging said tray lip, said housing including an electric motor, cell batteries within said housing for powering said motor, and an electric switch in a circuit between said batteries and said motor, said switch having manual control means for operating said motor in a forward or reverse direction, and said motor having an output shaft driving through a gear unit to said wheel means.

2. The combination as set forth in claim 1, wherein said wheel means comprises a drive wheel mounted upon an output shaft of said motor, said drive wheel being positioned adjacent the upper side of said tray lip, said output shaft being journaled within a pair of spaced apart legs integral with said housing, a vertical arm secured at its upper end to a side of said housing, the lower end of said arm having an integral horizontal bar, and said bar providing means for support of a pair of binding wheels of said crawler unit which bear against the underside of .said tray lip.

3. The combination as set forth in claim 2, wherein said support means for said binding wheels comprises a pair of spacedapart upstanding guide posts upon said bar, a vertically moveable frame carried between said posts, said frame having a pair of U-shaped brackets integral therewith, each of said U- shaped brackets including bearings for a shaft there across, each of said shafts supporting one of said binding wheels, and a binding post secured in selective vertical position to said bar providing a means for urging said frame upwardly for frictional pressure of said binding wheels against the underside of said tray lip.

4. The combination as set forth in claim 3, wherein said crawler unit further includes a rope clamp arm secured pivotally to said housing, said rope clamp arm having an opening at its lower end for securement to a rope, said rope clamp arm being pivotable between a vertical and a horizontal positron. 

